On Nov. 11, 1966, the Gemini 12 mission launched an astronaut crew into orbit and set the stage for NASA's Apollo program to land humans on the moon.

Gemini 12 was the last mission of the Gemini program. It had two astronauts on board: Jim Lovell and Buzz Aldrin . NASA wanted to send humans to the moon. But first, it needed to make sure crews had the right skills, like docking vehicles in space and taking spacewalks.

Before Gemini 12, astronauts struggled with spacewalks because there weren't enough handholds on their spacecraft. NASA made some spacewalk changes for Gemini 12. Aldrin performed three spacewalks and spent more than five hours working in space with no major problems. Gemini 12 also successfully docked to an unpiloted Agena booster that launched the same day.

The astronauts returned to Earth after four days in space. Both Aldrin and Lovell went on to join the Apollo program .…